Physical activity, sedentary time and breast cancer risk: a Mendelian randomisation study
Authors: Suzanne C Dixon-Suen, Sarah J Lewis, Richard M Martin, Dallas R English, Terry Boyle, Graham G Giles, Kyriaki Michailidou, Manjeet K Bolla, Qin Wang, Joe Dennis, Michael Lush, ABCTB Investigators, Thomas U Ahearn, Christine B Ambrosone, Irene L Andrulis, Hoda Anton-Culver, Volker Arndt, Kristan J Aronson, Annelie Augustinsson, Päivi Auvinen, Laura E Beane Freeman, Heiko Becher, Matthias W Beckmann, Sabine Behrens, Marina Bermisheva, Carl Blomqvist, Natalia V Bogdanova, Stig E Bojesen, Bernardo Bonanni, Hermann Brenner, Thomas Brüning, Saundra S Buys, Nicola J Camp, Daniele Campa, Federico Canzian, Jose E Castelao, Melissa H Cessna, Jenny Chang-Claude, Stephen J Chanock, Christine L Clarke, Don M Conroy, Fergus J Couch, Angela Cox, Simon S Cross, Kamila Czene, Mary B Daly, Peter Devilee, Thilo Dörk, Miriam Dwek, Diana M Eccles, A. Heather Eliassen, Christoph Engel, Mikael Eriksson, D. Gareth Evans, Peter A Fasching, Olivia Fletcher, Henrik Flyger, Lin Fritschi, Marike Gabrielson, Manuela Gago-Dominguez, Montserrat García-Closas, José A García-Sáenz, Mark S Goldberg, Pascal Guénel, Melanie Gündert, Eric Hahnen, Christopher A Haiman, Lothar Häberle, Niclas Håkansson, Per Hall, Ute Hamann, Steven N Hart, Michelle Harvie, Peter Hillemanns, Antoinette Hollestelle, Maartje J Hooning, Reiner Hoppe, John Hopper, Anthony Howell, David J Hunter, Anna Jakubowska, Wolfgang Janni, Esther M John, Audrey Jung, Rudolf Kaaks, Renske Keeman, Cari M Kitahara, Stella Koutros, Peter Kraft, Vessela N Kristensen, Katerina Kubelka-Sabit, Allison W Kurian, James V Lacey, Diether Lambrechts, Loic Le Marchand, Annika Lindblom, Sibylle Loibl, Jan Lubiński, Arto Mannermaa, Mehdi Manoochehri, Sara Margolin, Maria Elena Martinez, Dimitrios Mavroudis, Usha Menon, Anna Marie Mulligan, Rachel A Murphy, NBCS Collaborators, Heli Nevanlinna, Ines Nevelsteen, William G Newman, Kenneth Offit, Andrew F Olshan, Håkan Olsson, Nick Orr, Alpa Patel, Julian Peto, Dijana Plaseska-Karanfilska, Nadege Presneau, Brigitte Rack, Paolo Radice, Erika Rees-Punia, Gad Rennert, Hedy S Rennert, Atocha Romero, Emmanouil Saloustros, Dale P Sandler, Marjanka K Schmidt, Rita K Schmutzler, Lukas Schwentner, Christopher Scott, Mitul Shah, Xiao-Ou Shu, Jacques Simard, Melissa C Southey, Jennifer Stone, Harald Surowy, Anthony J Swerdlow, Rulla M Tamimi, William J Tapper, Jack A Taylor, Mary Beth Terry, Rob A E M Tollenaar, Melissa A Troester, Thérèse Truong, Michael Untch, Celine M Vachon, Vijai Joseph, Barbara Wappenschmidt, Clarice R Weinberg, Alicja Wolk, Drakoulis Yannoukakos, Wei Zheng, Argyrios Ziogas, Alison M Dunning, Paul D P Pharoah, Douglas F Easton, Roger L Milne, Brigid M Lynch
Journal: British Journal of Sports Medicine (2022)

Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.